Details

Autor(en) / Beteiligte

• Chen, Long-Fei
• He, Zhi-Bin
• Zhao, Wen-Zhi
• Ma, Lei
• Liu, Sheng-En
• Zhao, Li-Wen
• Yang, Shu-Ping
• Feng, Xiang-Yan

Titel

The long-term effects of thinning on soil respiration vary with season in subalpine spruce plantations

Ist Teil von

• Agricultural and forest meteorology, 2023-11, Vol.342, p.109756, Article 109756

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2023

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• •Thinning increased soil respiration (Rs) in the growing season.•Thinning decreased Rs in nongrowing season.•Thinning increased the temperature sensitivity of Rs in nongrowing season.•Nitrate nitrogen had the greatest effect on Rs after thinning in growing season.•Soil moisture had opposite effects on Rs in growing and nongrowing seasons. Thinning is a principal silvicultural practice in temperate plantations with potential impacts on soil respiration (Rs). However, most of the existing measurements of Rs dynamics after thinning have been performed during the growing season, while those in the nongrowing season have been seldom determined, even though recent evidence demonstrates that the nongrowing season Rs occupied a considerable proportion of the annual carbon (C) budgets in temperate forests. Here, we investigated the long-term (17 years) impacts of thinning on Rs in middle-aged subalpine spruce plantations in northwestern China. We found that thinning significantly (p < 0.001) increased Rs from 3.00 to 4.18 μmol m−2 s−1 in the growing season while significantly (p < 0.001) decreasing Rs from 1.05 to 0.90 μmol m−2 s−1 in the nongrowing season; additionally, thinning had no significant (p = 0.0989) effect on the Q10 value (temperature sensitivity of Rs) in the growing season, with values ranging from 2.10 to 2.44, while it significantly (p < 0.01) increased the Q10 value from 2.91 to 3.48 in the nongrowing season. In the growing season, increased nitrate nitrogen due to elevated soil moisture (SM) played a fundamental role in stimulating Rs by improving microbial biomass (MB) and fine root biomass, and increased soil temperature (ST) also contributed to the increases in MB and Rs. However, these variables and pathways were not applicable in the nongrowing season, when decreased dissolved organic C induced by decreased ST explained most of the decline in MB and Rs. Our results revealed that the long-term effects of thinning on the nongrowing season Rs were completely different from those in the growing seasons in subalpine spruce plantations. Furthermore, the greatly increased Q10 value in the nongrowing season indicated that a substantial increase in Rs can be expected in subalpine forests after thinning due to nongrowing season warming at high altitudes.